Magnetic chuck



FIG. 1 is a perspective view of the design for a magnetic chuck of the present invention;

FIG. 2 is a side elevational view of the magnetic chuck of FIG. 1;

FIG. 3 is a top plan view of the magnetic chuck of FIG. 2; and,

FIG. 4 is a bottom plan view of the magnetic chuck of FIG. 2. 

The ornamental design for a magnetic chuck, as shown. 